There is an ancient Chinese story about how giant pandas got their unique markings. A young girl who was a friend of these bears died and the pandas were struck with sorrow. They wept at the funeral and rubbed their eyes with their arms. The dark color from their arm bands was wiped onto their eyes. The bears then hugged themselves and marked their ears, shoulders, hind legs and rumps, resulting in the pattern seen today. The classification of A. melanoleuca has been a difficult one for researchers to agree upon. Giant pandas have several characteristics in common, like bamboo eating, with red pandas, who have sometimes been considered to be members of the raccoon family (but currently are also classified with bears). Today it is widely accepted with little doubt that that giant pandas belong to the bear family (Ward and Kynaston, 1995).
Giant pandas occupy temperate montane forests with dense stands of bamboo at altitudes of 1,2004,100 m asl (more typically 1,5003,000 m asl; Hu and Wei 2004). Habitat use depends both on the type and density of bamboo, the overstory (which influences the growth of bamboo), and the hillslope (Reid and Hu 1991). Giant pandas do not hibernate but they generally descend to lower elevations in the winter (Liu et al. 2002), and may take temporary shelter in hollow trees, rock crevices and caves.
Giant pandas spend about 55% of the day (both daytime and night-time) feeding, mainly on bamboo (Schaller et al. 1985, 1989). Bamboo comprises 99% of their diet. They utilize over 60 species of bamboo, but 35 species comprise their main food source (Hu and Wei 2004). They often use different species of bamboo in different elevational bands, varying use with the seasons (Pan et al. 2001, Loucks et al. 2003)
Pandas are often erroneously believed to be poor breeders, an impression rooted in the previous disappointing reproductive performance of captive animals (L et al. 2000). Studies of wild pandas, however, indicate that their reproductive rates are comparable to those of some other species of bears (Garshelis 2004, Harris 2004, Wang et al. 2004). Moreover, captive populations in China are now reproducing well.
Giant pandas are usually solitary, except during the mating season and while rearing a cub. During the MarchMay breeding season, females may breed with multiple males. Birthing, often in rock dens or hollow trees, occurs in AugustSeptember (Schaller et al. 1985, Zhu et al. 2001). One or two cubs are born, but the mother raises only one.
Threats to this species include poaching, habitat loss, human encroachment, and trouble breeding in captivity. Tourism around giant pandas' habitat means more hotels, waste disposal systems, cars, buses, etc. and less room for pandas. Remaining bamboo forests in China only support about 1,000 wild pandas. Thirteen panda reserves totaling an area of 6,227 square km make up half of the remaining habitat. Also, the habitat has been broken into about 20 different separate patches. The pandas have trouble migrating from one site to another. Although efforts are showing improvement compared to earlier years, the zoo population of about 100 pandas worldwide has yet to produce enough cubs to maintain itself. The first successful panda breeding came in 1980 at the Mexico City Zoo, however the infant died after 8 days. In August 1999 another cub was born at San Diego Zoo and seems to be flourishing. To protect the population in the wild, the Chinese government has many anti-poaching laws. Some violators of these laws have even been sentenced to death. In October 1989 the first executions for trading panda skins took place. China has also stopped commercial logging. In 1986 an education campaign took place among 5,000 villages. It attempted to teach farmers and villagers about panda protection and discourage them from cutting bamboo. In 1992 the Chinese government approved the National Conservation Program for the Giant Panda and its Habitat. Since the 1980s many programs have been put in place attempting to save these great animals. Success to breed them in captivity is looking more hopeful but in the wild the numbers are still low. Recent Chinese studies have shown that panda populations have actually been stable for 20 years, but all this effort still may not be enough to save this species (Ward and Kynaston, 1995; World Wildlife Fund, 2001; Massicot, 2001)
Formerly these pandas were found in hilly ravines at lower elevations, but populations have been forced into the mountains and they can now be found in temperate montane forest at 1,200 to 3,400 metres, where there is an abundance of bamboo (4).
Giant pandas have an extremely strict energy budget. They travel little and are usually foraging when they do move. Giant pandas can spend 10-12 hours a day feeding. Bamboo, the main source of pandas' diet (over 99%) is a very poor nutritional source but present all year round. Only about 17% of the nutrients found in the leaves and stalks are extracted. These bears make a trade-off to have a plentiful, easily obtained food source but with low nutritional value. Giant pandas are well-known for their upright feeding position which leaves their forelegs free to handle the bamboo stalks. This species has several special characteristics related to eating bamboo. The extra digit on the panda's hand helps the panda in tearing the bamboo. This adaptation also allows increased dexterity while handling bamboo. The stomach walls are extremely muscular to help digest the woody diet; and the gut is covered with a thick layer of mucus to protect against splinters (Ward and Kynaston, 1995; Malius, 2001; Massicot, 2001).
Foods eaten include: bamboo stems and shoots, fruits of plant matter like kiwi, small mammals, fish and insects.
Three range-wide surveys have been conducted, in the mid-1970s, mid-late1980s, and 20002002. All surveys were based on incidence of sign, but techniques varied, so results are not directly comparable. Present best estimates indicate a total wild population between 1,0002,000. Greater protection of forests and from poaching in recent years suggest that panda populations should be increasing, but this has not been confirmed empirically.
Results from the most recent survey, coordinated by the State Forestry Administration (SFA) of China and World Wildlife Fund (WWF), indicated a total population of ~1600 individuals. This is over 40% higher than previous estimates. It is believed that the increase in the estimated number of pandas is due largely to differences in survey methodology and a larger search area, as well as possibly an actual increase in panda population size in some areas. Conversely, in other areas, habitat conditions were deemed to be worse and panda numbers lower in 20002002 than in the 1980s survey.
The most recent population estimate was based on differentiating individual pandas from measurements of bamboo fragments in scats. It is known that different age classes of pandas have different bite-sizes of bamboo (Schaller et al. 1985), but the validity of differentiating individuals of the same age class based on bite-sizes has not been well tested. Recent information on DNA-identified scats suggests that the bite-size method may underestimate population size in some cases (e.g., dense populations; Zhan et al. 2006).
Many surviving wild giant panda subpopulations have fewer than 50 individuals (Loucks et al. 2001). No major reductions in the genetic diversity of these populations is apparent, although they likely experienced modest genetic losses from a much larger ancestral population (L 2001). Some controversial research suggests that the Qinling (Shaanxi Province) population is a genetically isolated and distinct subspecies (Wan et al. 2005)
Adults of this solitary species have well-defined home ranges and rarely meet, except in the mating season that runs from March to May (5). During this time, pandas signal their presence by marking trees and banks with scent secreted from glands located beneath the tail (6). They will also strip bark and occasionally males will dust bathe; dust particles become covered with the pandas' scent and then waft into the air (6). Males also call during this time, and these can be heard echoing through the mountains (7). Females give birth to a single cub that is born in an extremely immature stage of development; weighing only a tiny fraction (0.001%) of their mother's weight (5). The female cares for her cub in a den located in the base of a hollow tree or in a cave for the first few months of its life (4) (8). Young pandas remain dependent on their mother for a year, by which time they are weaned, but usually remain with their mothers until they are two years of age and sometimes longer (4) (8). During this time, females may leave their cubs to forage for days at a time and in the past these supposedly 'abandoned' cubs were taken into captivity (4). Pandas are unusual amongst the larger mammals for the extreme specialisation of their diet, which depends almost entirely on bamboo. Bamboo is a relatively abundant food source but has poor nutritional value; adults must spend around 14 hours a day feeding (4), and need to consume between 10 and 20 kg over 24 hours (8). They therefore alternate periods of feeding and resting throughout the day and night (7). Bamboo is evergreen and in winter pandas concentrate on leaves and stems, descending to lower altitudes in search of new shoots in spring (6). Despite their specialisation on bamboo, pandas will readily scavenge on meat should they come across it (7).